If Aizen does send someone to attack SS too it will be hilarious. It will be sad for the captains for them to come back to SS and see everything destroyed.
While the captains are in the living realm, Wonderweiss leads a pack of menos into Soul Society to, from his perspective, collect butterflies. Aizen could have seen his odd behavior and thought that it'd be a good way to break communcations, once Wonderweiss comes back with a mouth full of hell butterflies.